From 272d9252ab1b42128afee34e985ca1b51bd9fb30 Mon Sep 17 00:00:00 2001
From: hselasky <hselasky@FreeBSD.org>
Date: Tue, 5 Aug 2014 18:35:34 +0000
Subject: [PATCH] Add handler for read-back of USB audio volume levels.

---
 sys/dev/usb/gadget/g_audio.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/sys/dev/usb/gadget/g_audio.c b/sys/dev/usb/gadget/g_audio.c
index a1d23944ff16..fdcb5c8c3349 100644
--- a/sys/dev/usb/gadget/g_audio.c
+++ b/sys/dev/usb/gadget/g_audio.c
@@ -587,6 +587,16 @@ g_audio_handle_request(device_t dev,
 				*plen = 0;
 			}
 			return (0);
+		} else if ((req->bmRequestType == UT_READ_CLASS_INTERFACE) &&
+		    (req->bRequest == 0x81 /* get value */ )) {
+
+			if (offset == 0) {
+				*plen = sizeof(sc->sc_volume_setting);
+				*pptr = &sc->sc_volume_setting;
+			} else {
+				*plen = 0;
+			}
+			return (0);
 		} else if ((req->bmRequestType == UT_WRITE_CLASS_INTERFACE) &&
 		    (req->bRequest == 0x01 /* set value */ )) {